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Magnesium

Magnesium is a dietary mineral. Magnesium deficiency is common in developed countries and is associated with diabetes and other conditions. A prolonged lack of magnesium in the diet can lead to muscle cramps, raised blood pressure, and reduced insulin sensitivity.

Our evidence-based analysis on magnesium features 432 unique references to scientific papers.

Research analysis led by and reviewed by the Examine team.
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Summary of Magnesium

Primary information, health benefits, side effects, usage, and other important details

What is magnesium?

Magnesium is an essential dietary mineral and the second most prevalent intracellular cation in the body. It also serves as a cofactor for over 600 enzymes. Most notably, magnesium is required for energy production, carbohydrate metabolism, and DNA and protein synthesis.

Magnesium is also an antagonist of calcium in the body and is required for vitamin D synthesis and activation. As such, magnesium deficiency can inhibit the potential benefits of vitamin D supplementation.[1]

Magnesium is abundant in green leafy vegetables, nuts, seeds, legumes, and whole grains. Inadequate magnesium intake is common in developed countries, as Western diets tend to contain a very low content of the aforementioned foods and are rich in refined grains and processed foods, which are poor sources of magnesium.

Magnesium deficiency increases blood pressure, reduces insulin sensitivity, and causes neural excitation. Consequently, low serum magnesium levels are associated with a wide variety of conditions, including obesity, type 2 diabetes, cardiovascular disease, metabolic syndrome, and osteoporosis.[2]

Magnesium supplementation is not very effective at reducing fat mass or muscle cramps.[3] Further evidence is needed to determine whether magnesium supplementation can improve sleep parameters.[4]

What are magnesium's main benefits?

Magnesium supplementation modestly reduces (a) systolic and diastolic blood pressure (by about −2 mmHg each),[5][6][7] (b) fasting blood glucose in people with type 2 diabetes or at an increased risk of type 2 diabetes,[8][9] and (c) C-reactive protein levels.[10] The magnitude of improvement is larger in people with magnesium deficiency.

Magnesium supplementation can also reduce the frequency and intensity of migraine.[11][7]

What are magnesium's main drawbacks?

There aren’t many side effects associated with magnesium supplementation because, in healthy people, the body will only absorb as much as it needs. With that said, high doses of some magnesium salts (e.g. hydroxide, oxide, and citrate) are used as laxatives; therefore, excessive doses may cause gastrointestinal distress and diarrhea.

How does magnesium work?

Many of magnesium’s beneficial effects are related to (a) its role as an antagonist of calcium in the body and (b) its role in regulating inflammation and oxidative stress,[12] which are intimately involved in the development of chronic diseases (e.g., type 2 diabetes, hypertension).

Magnesium regulates the insulin signaling pathway and affects insulin secretion from pancreatic beta cells.[13] In the case of magnesium deficiency, insulin secretion is dysfunctional.[14] Magnesium deficiency can also reduce glucose tolerance because many of the enzymes involved in carbohydrate metabolism require magnesium.[15]

Magnesium affects blood pressure mainly by modulating calcium concentrations and therefore affecting vascular tone.[16] Additionally, it supports vasodilation by stimulating the production of nitric oxide.[16] These properties are also pivotal to magnesium’s effects on migraine.[17]

Lastly, magnesium blocks NMDA receptors, whose activation is associated with migraine. With magnesium deficiency, NMDA receptors allow an increased influx of calcium, triggering the release of glutamate, which binds to and activates NMDA receptors.[17]

📝 Want a quick summary of magnesium’s health benefits?

We've analyzed over 100 studies to summarize the research on magnesium’s potential health benefits.

How to Take

Recommended dosage, active amounts, other details

The standard dosage for magnesium for adults is 250–450 milligrams per day (mg/day). However, the Tolerable Upper Intake Level for elemental magnesium from dietary supplements is 350 mg/day, because this was the highest dose determined not to cause diarrhea in most people. Magnesium should be taken with food.

Magnesium L-threonate is not recommended to attenuate a magnesium deficiency because it contains less elemental magnesium per dose than other forms. Magnesium oxide and hydroxide are also suboptimal choices because they are very poorly absorbed and gastrointestinal side effects are more common with them. Magnesium citrate and lactate are generally good choices for supplementation.

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Human Effect Matrix

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The Human Effect Matrix summarizes human studies to tell you what effects Magnesium has on your body, how much evidence there is, and how strong these effects are.

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Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Outcome Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
Notes
grade-b Notable Moderate See all 9 studies
There appears to be a significant reduction in blood pressure assuming one of two conditions is met, either the subject is low in magnesium levels in the body (deficient) or if the subject has elevated blood pressure (140/90 or above), with the latter not requiring a deficiency to precede the blood pressure reducing effects
grade-b Notable High See all 6 studies
Has the capacity to increase serum magnesium stores, but this is somewhat unreliable and may be dependent on the person being deficient in magnesium prior to supplementation
grade-b Minor High See all 4 studies
There appears to be a reduction in asthmatic symptoms associated with magnesium supplementation to a low degree, with the one study using corticosteroids alongside magnesium finding no effect. There may be a role for magnesium in aiding untreated asthma, but already medicated situations are not certain
grade-b Minor Moderate See all 8 studies
There appears to be some reduction in blood glucose in diabetics and persons with elevated glucose with magnesium supplementation, which may be secondary to better insulin functioning from the pancreas. The reduction in glucose is not overly impressive and is somewhat unreliable, and increases in glucose have been noted to occur during exercise when magnesium is supplemented in healthy persons
grade-b Minor Low See all 3 studies
More evidence than not suggest no significant effect on HbA1c levels, but one study suggests a decent decrease with the other two studies trending towards a decrease. There may be a role for magnesium in reducing HbA1c levels to a minor degree
grade-b Minor Moderate See all 6 studies
Decreases in fasting insulin appear to occur over long term supplementation with magnesium in persons at risk for diabetes or already with the disease state; decreases in insulin may not occur in normoglycemic persons
grade-b Minor High See all 4 studies
There appears to be increases in insulin sensitivity as assessed by HOMA-IR, which is thought to be secondary to aiding pancreatic function
grade-b - High See all 4 studies
For the most part, there is no significant direct influence of magnesium on HDL-C levels. Some counter evidence suggests it may occur vicariously through betterment of glycemic control in diabetics, but that is not always seen
grade-b - Very High See all 6 studies
For the most part, no significant influence of magnesium supplementation on triglycerides
grade-b - Very High See all 4 studies
No evidence to support a role for magnesium in inducing alterations in body weight
grade-c Notable - See study
The one study to assess aerobic exercise capacity noted a significant improvement during extreme physical stress (triathletes), which is notable and needs replication
grade-c Notable - See study
The one study to measure muscle oxygenation in high intensity exercise noted quite a remarkable increase in oxygenation in healthy athletes; this needs to be replicated
grade-c Minor - See study
An increase in bone mineral density has been noted with magnesium supplementation
grade-c Minor Moderate See 2 studies
Possible reduction in C-Reactive protein, but these changes are unreliable
grade-c Minor - See study
One study has noted a reduction in symptoms of migraines associated with oral magnesium supplementation
grade-c Minor Moderate See 2 studies
Possible but unreliable increases in osteocalcin
grade-c Minor Very High See all 5 studies
A moderate reduction in symptoms of PMS has been noted with magnesium supplementation in most trials, though evidence quality tends to be low and it's difficult to have great confidence in the results. One study found an apparent additive effect of magnesium and vitamin B6.
grade-c Minor Very High See 2 studies
An improvement in sleep quality has been noted in persons with poor sleep quality, no studies assess persons with normal sleep function
grade-c Minor - See study
A reduction in symptoms associated with diabetic neuropathy has been noted with magnesium supplementation
grade-c - - See study
No significant influence on cortisol seen with magnesium supplementation
grade-c - - See study
No evidence to support a reduction in pregnancy related leg cramps
grade-c - Very High See 2 studies
No significant influence on LDL cholesterol levels seen with magnesium supplementation
grade-c - - See study
No significant influences on testosterone levels noted with magnesium intake
grade-c - Very High See 2 studies
No significant influence on total cholesterol levels seen with magnesium supplementation
grade-d Minor Very High See 2 studies
Reduced depressive symptoms have been found in elderly diabetics
grade-d Minor - See study
One study found an improvement in the severity of symptoms.
grade-d Minor - See study
Decreased symptoms associated with tinnitus have been noted following magnesium supplementation
grade-d - - See study
grade-d - - See study
No significant influence on oxidation rates of LDL cholesterol
grade-d - - See study

Studies Excluded from Consideration

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Frequently Asked Questions and Articles on Magnesium

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When it comes to increasing your testosterone, quality sleep, physical activity, and weight management come first. A few supplements can help sustain healthy testosterone levels, but most supplements marketed as testosterone boosters don’t work, though some can make you believe they do by boosting your libido.
Does ZMA cause weird dreams?
It is possible that ZMA can cause weird dreams, and the anecdotes support this; however, since this has not been directly investigated the best 'proof' that can be given is weak.
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Things to Note

Is a Form Of

Primary Function:

Do Not Confuse With

Manganese

Goes Well With

  • Magnesium is typically non-stimulatory. If deficient, high acute doses of supplemental magnesium can be slightly sedative.

📝 Want a quick summary of magnesium’s health benefits?

We've analyzed over 100 studies to summarize the research on magnesium’s potential health benefits.

Click here to see all 432 references.